The angles
The Ascendant is the zodiacal degree rising at the eastern horizon. Its opposite is the Descendant. The Midheaven marks the meridian intersection with the ecliptic, and the IC is opposite it. These depend on time and location; Asteria calculates the Ascendant and Midheaven when birth time is known.
Whole-sign houses
Asteria uses whole-sign houses: the entire rising sign becomes the first house, and subsequent signs form the remaining eleven houses. The Ascendant and Midheaven remain distinct points; the Midheaven is not necessarily in the tenth whole-sign house.
Other systems
Placidus, Koch, equal-house, and other systems divide the chart differently. House placements can change when systems change. Asteria does not label whole-sign results as Placidus. Near the geographic poles the Ascendant becomes unstable; houses are omitted above 66 degrees latitude.
Keep exploring
Study the vocabulary and traditions in the AstroWiki reference. Astronomical calculations use Astronomy Engine. Interpretations are original Asteria editorial content and are not scientific predictions.